Many N-(3-(((aryl)amino)sulfonyl)-1H-1,2,4-triazol-5-yl)amines (I), ##STR1## their preparation, and their value as intermediates in the manufacture of substituted 1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonanilide herbicides (II) ##STR2## have been described in U.S. Pat. Nos. 4,734,123 and 4,755,212. Recently, the direct preparation of N-(3-(((aryl)amino)sulfonyl)-1H-1,2,4-triazol-5-yl)amines (I) from substituted anilines and from 5-amino-3-chlorosulfonyl-1,2,4-triazole (III) has been reported. ##STR3## The 5-amino-3-chlorosulfonyl-1,2,4-triazole (III) is obtained by treating 5-amino-3-mercapto-1,2,4-triazole (IV) with chlorine in an aqueous acid medium until the reaction is substantially complete. ##STR4##
Although the direct chlor-oxidation of 5-amino-3-mercapto-1,2,4-triazole to 5-amino-3-chlorosulfonyl-1,2,4-triazole occurs in relatively good yield, the process is plagued by mixing problems associated with intractable slurries which complicate scale-up both with respect to chlorine dispersion and to heat transfer. In addition, the product is contaminated with 3-amino-1,2,4-triazole (V) ##STR5## as a major by-product of the chlor-oxidation process. The discovery of an improved process which would alleviate the mixing difficulties associated with the intractable slurries and which would eliminate the formation of the major contaminant would be highly desirable.